[MOC] 4x4 Mini Extreme Samurai

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I would like to present my latest experiment, an extreme off-roader mini Samurai - yes, another one .

The goal of this project was to see, what is the tiniest chassis I can build, with suspension, steering, and 4x4 drivetrain.

I succeed to shrink down to 10 studs width, and for that I built the chassis and the body. The position of the IR receiver might be "illegal", I couldn't place it in LDD, but in reality it works without any problem.

Well, the result is quite fine, but the front axle is not stable enough, too much slack left in it, and the gears can slip under hevier load. I tried to reinforce with rubber band, which brought some improvement, but not as much, as I was hoped for. Maybe one day I will build a completely new one, although as it is, pulling a 42043 is no problem for this tiny monster.

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Wow, this is very impressive! 4x4 and suspension in a 10 wide build? Amazing. I still haven't worked out how you did the steering (I can't access the file). Great Job

The servo is directly mounted on the front axle, and directly driven. I had to add some stabilization for the steering rack, without it the gear easily could spring, given the slack of the construction.

That was a fast rework, wow! Althugh it will not work fine. The servo must be separated from the bodywork. As mentioned above, it is directly mounted to the axle, for this suspension setup needs space to move. Also the big wheels will come loose much easier, I think with different axles it could be a nice monster truck, so the redesign direction is good.

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The servo is directly mounted on the front axle, and directly driven. I had to add some stabilization for the steering rack, without it the gear easily could spring, given the slack of the construction.

It still can happen, but not at an annoying level.

That was a fast rework, wow! Althugh it will not work fine. The servo must be separated from the bodywork. As mentioned above, it is directly mounted to the axle, for this suspension setup needs space to move. Also the big wheels will come loose much easier, I think with different axles it could be a nice monster truck, so the redesign direction is good.

Ah how did I miss that about servo

I might give this a second thought, it deserves the attention. With such a short wheelbase and massive wheels, the entry and exit angles are nearly 90 degrees, making this perfect for descending/ascending hills (assuming it doesn't flip over).

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Awesome suspension setup! One suggestion though. I belive you dont need such high gearing for the drive and you can easily repalce at least a pair of 12:20 gears with 16:16.

I think you made one of the smallest drive axle, at least AFAIK.

Oh one more suggestion, this part might be helpfull in the axles for future buids:

I wanted to have great torque, and crawling speed, so that's why I decided for double reduction, but of course every other options are open.

I was playing around with that part, but given the 3 stud width, it allows "only" 11 stud wide axle build... oooor the end elements must be half stud wide. Hmmm, worth to think about.

It tend to lift its left front wheel all the time. Might the centre of gravity be a little to high?

It is a bit indeed, but as JJ2 wrote, it is the torque twist. First, I have built the final gearing mirrored, flat surface, straigt forward ride: I was lucky to see the first off-road lowrider in my life!

Edited May 2, 2016 by agrof

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It is a bit indeed, but as JJ2 wrote, it is the torque twist. First, I have built the final gearing mirrored, flat surface, straigt forward ride: I was lucky to see the first off-road lowrider in my life!

Yep, I know all about it...my 6x6 trucks do have the same problem... Indeed having the axles powered in opposite directions sort of eliminates that torque twist. Do I get you right that it is now improved?

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Increased wheel travel... almost, because I had to mount them from opposite side as usual happens, so 1 beam height is lost, but still fits. Also the front axle construction with built-in servo makes a lot limitation.